Conventional color reversal light-sensitive materials comprise a support having thereon at least two silver halide emulsion layers having mutually different color sensitivities. Each of these emulsion layers is incorporated with a color-forming coupler capable of forming a color image with a color complementary to the color corresponding to wavelength in light to which the emulsion layer per se is sensitive. (The term "color sensitivity" herein means a property capable of being sensitive to light in either red, green or blue region of the visible spectrum.)
More conventional types of color reversal light-sensitive materials possess a layer structure comprising, in order, a support, a red-sensitive silver halide emulsion layer comprising a silver halide sensitized with a red-sensitizing dye and a coupler capable of forming a cyan dye image, an interlayer, a green-sensitive silver halide emulsion layer comprising a silver halide sensitized with a green-sensitizing dye and a coupler capable of forming a magenta dye image, an interlayer (yellow filter layer, in many cases), a blue-sensitive silver halide emulsion layer sensitive to light in the blue region of the spectrum and containing a coupler capable of forming a yellow dye image. Each of the emulsion layers may be composed of a low sensitive (or slow speed) layer and a high sensitive (or high speed) layer which have an identical color sensitivity.
In such color light-sensitive materials, the molar ratio of silver halide to the coupler (hereinafter referred to as silver/coupler ratio) contained in each silver halide emulsion layer does not always vary widely from layer having one color sensitivity to layer having different color sensitivity thereto. In some cases, however, a certain emulsion layer (in particular, a green-sensitive emulsion layer) is intentionally endowed with a silver/coupler ratio greater than those of other layers having different color sensitivities, so as to improve the graininess of dye images to be formed in said emulsion layer.
The present inventors have now discovered that migration, during storage, of a sensitizing dye (e.g., a red-sensitizing dye) from an emulsion layer to other emulsion layers having different color sensitivities can be effectively prevented by incorporating silver halide grains having been previously fogged on their surfaces (hereinafter referred to as fogged silver halide grains) into an interlayer, in particular, into an interlayer between a green-sensitive emulsion layer and a red-sensitive emulsion layer.
In light-sensitive materials comprising an interlayer which contains fogged silver halide grains, silver halide emulsion layers adjacent to the interlayer tend to fog. Consequently, not only lowered maximum densities but also deterioration in gradation may result when such light-sensitive materials are subjected to a color reversal processing. The above problem can be solved by the provision of an interlayer not containing fogged silver halide grains (hereinafter referred to as fog prevention layer) between the interlayer containing fogged silver halide grains and a silver halide emulsion layer which is adjacent thereto. However, this technique, when applied to both green- and red-sensitive emulsion layers in a light-sensitive material, brings about an undesirable increase in the thickness of coated films and, as a result, deterioration in the sharpness of images. It is therefore preferable to prevent fogs in at least one of the two layers by a means other than the provision of such a fog prevention layer. According to investigations by the present inventors, the above problem can be solved effectively by raising the silver/coupler ratio (based on moles) in silver halide emulsion layers adjacent to said interlayer in which the fogged silver halide grains are contained, so as to compensate the reduction in the amount of silver caused by said fogs.
However, when a silver halide emulsion having a high silver/coupler ratio is applied to a photographic light-sensitive material in order to improve graininess and/or to compensate the reduction in silver amount of silver caused by said fogs, such a silver halide emulsion layer shows an markedly decreased change in its sensitivity against the variation in the concentration of potassium bromide contained in the first developer used for the color reversal processing thereof, in comparison with those changes in other emulsion layers. Although this phenomenon may seem to be advantageous, it could cause a problem with regard to color balance. In other words, when a light-sensitive material comprising such a silver halide emulsion layer is treated with an exhausted first developer, there would result a deteriorated color balance between such an emulsion layer and other emulsion layers. This phenomenon becomes conspicuous in such cases where silver/coupler ratio in a silver halide emulsion layer is greater by a factor of at least 5, in particular, by a factor of at least 10, than those ratios in other silver halide emulsion layers having different color sensitivities. This kind of problem will not occur with a light-sensitive material in which all the emulsion layers are provided with high silver/coupler ratios. However, such a light-sensitive material would be impracticably costly and require a prolonged period of time in the desilvering step of the color reversal processing thereof.
Generally, because the concentration of potassium bromide contained in the first developer of color reversal processing varies depending upon degree of exhaustion of processing solution, it is practically useful to provide color reversal light-sensitive material which is prevented from deterioration in color balance due to the variation in the concentration of potassium bromide contained in the first developer of color reversal processing.